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      7.7.&nbsp;The Bash Shell Startup Files
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        Linux From Scratch - Version 8.0
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      <h3>
        Chapter&nbsp;7.&nbsp;System Configuration
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    <div class="sect1" lang="en" xml:lang="en">
      <h1 class="sect1">
        <a id="ch-scripts-profile" name="ch-scripts-profile"></a>7.7. The
        Bash Shell Startup Files
      </h1>
      <p>
        The shell program <span class=
        "command"><strong>/bin/bash</strong></span> (hereafter referred to as
        <span class="quote">&ldquo;<span class="quote">the
        shell</span>&rdquo;</span>) uses a collection of startup files to
        help create an environment to run in. Each file has a specific use
        and may affect login and interactive environments differently. The
        files in the <code class="filename">/etc</code> directory provide
        global settings. If an equivalent file exists in the home directory,
        it may override the global settings.
      </p>
      <p>
        An interactive login shell is started after a successful login, using
        <span class="command"><strong>/bin/login</strong></span>, by reading
        the <code class="filename">/etc/passwd</code> file. An interactive
        non-login shell is started at the command-line (e.g., <code class=
        "prompt">[prompt]$</code><span class=
        "command"><strong>/bin/bash</strong></span>). A non-interactive shell
        is usually present when a shell script is running. It is
        non-interactive because it is processing a script and not waiting for
        user input between commands.
      </p>
      <p>
        For more information, see <span class="command"><strong>info
        bash</strong></span> under the <span class="emphasis"><em>Bash
        Startup Files and Interactive Shells</em></span> section.
      </p>
      <p>
        The files <code class="filename">/etc/profile</code> and <code class=
        "filename">~/.bash_profile</code> are read when the shell is invoked
        as an interactive login shell.
      </p>
      <p>
        The base <code class="filename">/etc/profile</code> below sets some
        environment variables necessary for native language support. Setting
        them properly results in:
      </p>
      <div class="itemizedlist">
        <ul>
          <li class="listitem">
            <p>
              The output of programs translated into the native language
            </p>
          </li>
          <li class="listitem">
            <p>
              Correct classification of characters into letters, digits and
              other classes. This is necessary for <span class=
              "command"><strong>bash</strong></span> to properly accept
              non-ASCII characters in command lines in non-English locales
            </p>
          </li>
          <li class="listitem">
            <p>
              The correct alphabetical sorting order for the country
            </p>
          </li>
          <li class="listitem">
            <p>
              Appropriate default paper size
            </p>
          </li>
          <li class="listitem">
            <p>
              Correct formatting of monetary, time, and date values
            </p>
          </li>
        </ul>
      </div>
      <p>
        Replace <em class="replaceable"><code>&lt;ll&gt;</code></em> below
        with the two-letter code for the desired language (e.g., <span class=
        "quote">&ldquo;<span class="quote">en</span>&rdquo;</span>) and
        <em class="replaceable"><code>&lt;CC&gt;</code></em> with the
        two-letter code for the appropriate country (e.g., <span class=
        "quote">&ldquo;<span class="quote">GB</span>&rdquo;</span>).
        <em class="replaceable"><code>&lt;charmap&gt;</code></em> should be
        replaced with the canonical charmap for your chosen locale. Optional
        modifiers such as <span class="quote">&ldquo;<span class=
        "quote">@euro</span>&rdquo;</span> may also be present.
      </p>
      <p>
        The list of all locales supported by Glibc can be obtained by running
        the following command:
      </p>
      <pre class="userinput">
<kbd class="command">locale -a</kbd>
</pre>
      <p>
        Charmaps can have a number of aliases, e.g., <span class=
        "quote">&ldquo;<span class="quote">ISO-8859-1</span>&rdquo;</span> is
        also referred to as <span class="quote">&ldquo;<span class=
        "quote">iso8859-1</span>&rdquo;</span> and <span class=
        "quote">&ldquo;<span class="quote">iso88591</span>&rdquo;</span>.
        Some applications cannot handle the various synonyms correctly (e.g.,
        require that <span class="quote">&ldquo;<span class=
        "quote">UTF-8</span>&rdquo;</span> is written as <span class=
        "quote">&ldquo;<span class="quote">UTF-8</span>&rdquo;</span>, not
        <span class="quote">&ldquo;<span class=
        "quote">utf8</span>&rdquo;</span>), so it is safest in most cases to
        choose the canonical name for a particular locale. To determine the
        canonical name, run the following command, where <em class=
        "replaceable"><code>&lt;locale name&gt;</code></em> is the output
        given by <span class="command"><strong>locale -a</strong></span> for
        your preferred locale (<span class="quote">&ldquo;<span class=
        "quote">en_GB.iso88591</span>&rdquo;</span> in our example).
      </p>
      <pre class="userinput">
<kbd class="command">LC_ALL=<em class=
"replaceable"><code>&lt;locale name&gt;</code></em> locale charmap</kbd>
</pre>
      <p>
        For the <span class="quote">&ldquo;<span class=
        "quote">en_GB.iso88591</span>&rdquo;</span> locale, the above command
        will print:
      </p>
      <pre class="screen">
<code class="computeroutput">ISO-8859-1</code>
</pre>
      <p>
        This results in a final locale setting of <span class=
        "quote">&ldquo;<span class=
        "quote">en_GB.ISO-8859-1</span>&rdquo;</span>. It is important that
        the locale found using the heuristic above is tested prior to it
        being added to the Bash startup files:
      </p>
      <pre class="userinput">
<kbd class="command">LC_ALL=&lt;locale name&gt; locale language
LC_ALL=&lt;locale name&gt; locale charmap
LC_ALL=&lt;locale name&gt; locale int_curr_symbol
LC_ALL=&lt;locale name&gt; locale int_prefix</kbd>
</pre>
      <p>
        The above commands should print the language name, the character
        encoding used by the locale, the local currency, and the prefix to
        dial before the telephone number in order to get into the country. If
        any of the commands above fail with a message similar to the one
        shown below, this means that your locale was either not installed in
        Chapter 6 or is not supported by the default installation of Glibc.
      </p>
      <pre class="screen">
<code class=
"computeroutput">locale: Cannot set LC_* to default locale: No such file or directory</code>
</pre>
      <p>
        If this happens, you should either install the desired locale using
        the <span class="command"><strong>localedef</strong></span> command,
        or consider choosing a different locale. Further instructions assume
        that there are no such error messages from Glibc.
      </p>
      <p>
        Some packages beyond LFS may also lack support for your chosen
        locale. One example is the X library (part of the X Window System),
        which outputs the following error message if the locale does not
        exactly match one of the character map names in its internal files:
      </p>
      <pre class="screen">
<code class=
"computeroutput">Warning: locale not supported by Xlib, locale set to C</code>
</pre>
      <p>
        In several cases Xlib expects that the character map will be listed
        in uppercase notation with canonical dashes. For instance,
        "ISO-8859-1" rather than "iso88591". It is also possible to find an
        appropriate specification by removing the charmap part of the locale
        specification. This can be checked by running the <span class=
        "command"><strong>locale charmap</strong></span> command in both
        locales. For example, one would have to change
        "de_DE.ISO-8859-15@euro" to "de_DE@euro" in order to get this locale
        recognized by Xlib.
      </p>
      <p>
        Other packages can also function incorrectly (but may not necessarily
        display any error messages) if the locale name does not meet their
        expectations. In those cases, investigating how other Linux
        distributions support your locale might provide some useful
        information.
      </p>
      <p>
        Once the proper locale settings have been determined, create the
        <code class="filename">/etc/profile</code> file:
      </p>
      <pre class="userinput">
<kbd class="command">cat &gt; /etc/profile &lt;&lt; "EOF"
<code class="literal"># Begin /etc/profile

export LANG=<em class=
"replaceable"><code>&lt;ll&gt;_&lt;CC&gt;.&lt;charmap&gt;&lt;@modifiers&gt;</code></em>

# End /etc/profile</code>
EOF</kbd>
</pre>
      <p>
        The <span class="quote">&ldquo;<span class=
        "quote">C</span>&rdquo;</span> (default) and <span class=
        "quote">&ldquo;<span class="quote">en_US</span>&rdquo;</span> (the
        recommended one for United States English users) locales are
        different. <span class="quote">&ldquo;<span class=
        "quote">C</span>&rdquo;</span> uses the US-ASCII 7-bit character set,
        and treats bytes with the high bit set as invalid characters. That's
        why, e.g., the <span class="command"><strong>ls</strong></span>
        command substitutes them with question marks in that locale. Also, an
        attempt to send mail with such characters from Mutt or Pine results
        in non-RFC-conforming messages being sent (the charset in the
        outgoing mail is indicated as <span class="quote">&ldquo;<span class=
        "quote">unknown 8-bit</span>&rdquo;</span>). So you can use the
        <span class="quote">&ldquo;<span class="quote">C</span>&rdquo;</span>
        locale only if you are sure that you will never need 8-bit
        characters.
      </p>
      <p>
        UTF-8 based locales are not supported well by some programs. Work is
        in progress to document and, if possible, fix such problems, see
        <a class="ulink" href=
        "http://www.linuxfromscratch.org/blfs/view/8.0/introduction/locale-issues.html">
        http://www.linuxfromscratch.org/blfs/view/8.0/introduction/locale-issues.html</a>.
      </p>
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